1. Field of the Invention
This invention relates to a roentgenography of flexible skeletons, especially vertebral columns (backbones) of vertebrate animal including Homo sapiens and the devices used therefor, and more particularly to a roentgenography and the devices used therefor by which the shape of a vertebral column can be clearly photographed in such that X-ray patterns of the adjacent vertebrae are not overlapped one another by utilizing such a characteristic of a vertebral column composed of cervical vertebrae, thoracic spines, lumbar vertebrae and the like that the column may be artificially curved.
2. Description of the Related Art
In even the latest technology in which bones are photographed by the use of X-ray to precisely determine forms of the bones from the images thereof which have been taken on films, X-ray films are applied while maintaining the same in a planar state which remains unchanged. In this manner, however, there arises an extremely inconvenient problem, when a vertebral column composed of a number of continuous vertebrae is photographed by the use of a conventional flat photographic stand. More specifically, as schematically shown in FIG. 10, both of a vertebra shadow 16 and an intervertebral space shadow 17 are clearly photographed in the central portion of an X-ray film 10, while vertebra shadows 16 positioned near to the opposite end portions of the X-ray film comes to extend lengthily so that the resulting intervertebral space shadows 17 become obscure as indicated by arrows A. In this connection, for the sake of simple explanation, vertebrae 14 are illustrated by simple cubes, besides it is illustrated in such that a length of an intervertebral space 15 is extremely broaden and a distance between an X-ray film 10 and an X-ray tube 11 is far shorter than that in reality in FIG. 10. While the illustration has been made exaggeratedly in FIG. 10, in short, the vertebrae positioned immediately below the X-ray tube 11 are clearly photographed because the pattern of such a vertebra is not covered by shadows of both the adjacent vertebrae. On the contrary, X-ray comes to be irradiated more obliquely with increase in a distance from the X-ray tube 11, so that vertebral shadows 16 positioned near to the opposite ends of the X-ray film 10 extend lengthily. As a result, the adjacent vertebra shadows positioned near to the opposite ends of the film are overlapped one another as described above, so that the intervertebral space shadows 17 positioned near to the opposite ends of the film become obscure.
Because of the above described disadvantage involved in the conventional flat photographic stand, an affected part of disc hernia could not be heretofore ascertained by a shot of photographing in case of, for example, making a diagnosis of such disc hernia. Although an approximate position of the affected part can be decided by a prior neurological examination therefor, in order to make a more positive diagnosis it is required that roentgenograms are taken several times while shifting from an expected position little by little to obtain slightly different patterns on several films, and the resulting patterns on the several films are checked to collectively judge the affected part. As a result, roentgenographic engineers who take roentgenograms and physicians or veterinary surgeons who read such roentgenograms require extra labor, and further extra expenses for films and the development therefor are required, besides it results in three to four times higher X-irradiation upon patients.
On one hand, as a film sealing case for hermetically sealing an X-ray film, such a case which is manufactured by curving a flat rectangular cassette into a convex shape as shown in FIG. 11 is available on the market. Such a convexly curved cassette 18 shown in FIG. 11 is composed of a convexly formed surface cover 19 and a back plate 20 having the same shape as that of the surface cover, and the former is hinged to the latter to form a single swing structure wherein an intensifying screen is attached to the back of the surface cover 19 and a lead plate is embedded in the back plate 20. This cassette is a special cassette for photographing a movable part of human body such as joints of neck, shoulder, knee, coxa and the like. For example, in case of a shoulder joint, the convexly curved cassette is held by a patient's armpit and then, a roentgenogram is photographed. In case of taking a roentgenogram of cervical vertebrae, the convexly curved cassette 18 is placed like a pillow under the neck of a patient 12 who lies on a horizontal stand as shown in FIG. 12, and X-ray is irradiated over the patient's throat. However, even on a flat photographic stand, the inconvenience as described above is observed and accordingly, a deformation in an X-ray pattern due to a convexly curved cassette becomes more remarkable, so that such convexly curved cassette could not have absolutely been utilized for roentgenography of vertebral columns.
Furthermore, a small-sized X-ray film being hermetically sealed with a lead foil sack is used for inserting the same into a patient's mouth in a dental field. In this case, an X-ray tube is allowed to come near the face of a patient sat on a chair, and X-ray is irradiated from the outside of patient's teeth. Under the circumstances, such film sealing case of dental use is forced onto the inside of a tooth row, so that a roentgenogram is taken in such a manner that an X-ray film has been curved in a convex shape.
Moreover, a flexible cassette which can be freely bent is available on the market for use in non-destructive inspection of a structure having a bent portion such as steel pipes and the like. In case of using such flexible cassette, the cassette is attached to a bent portion of the structure with the use of a gummed cloth tape or the like in such that the flexible cassette is curved convexly or concavely in correspondence with a curved condition of the bent portion, and a roentgenogram is taken by allowing a portable X-ray tube to come near the bent portion. However, even if such a flexible cassette is utilized by convexly or concavely curving the same, a structure involves a variety of shapes. Accordingly, such a technical idea that each of curvatures of a structure is measured one by one, and then X-ray is irradiated from the center of the circular arc thus measured has never been heretofore proposed.